Hydrozoa and Ctenophora. 115 
No pigment can be detected in any part. The bell is of a dead milky white, 
translucent but not at all transparent. In the living medusa it was if anything more 
opaque than it is in specimens preserved in formalin. The gonads, the tentacles 
and the upper part of the manubrium are less translucent than the remainder of the 
organism. 
The four radial canals are of moderate breadth. Between each two of them there 
are about 10 centripetal canals, some of which reach upwards almost to the base 
of the stomach, while others are quite short. Neither the number nor the arrange- 
ment of these canals is constant even in the different radii of the same medusa, but 
as a rule long and short canals alternate. 
The gonads, in the male, are lamelliform and slightly folded in an irregular 
manner. They are attached below the radial canals near the base of the stomach by 
short peduncles and when ripe hang down as free structures at least half way to the 
velum. In this condition they are bulky and probably influence the shape of the bell. 
The manubrium is highly contractile but can be extended as far down as the 
mouth of the bell. It is stout even when ex- 
tended so far. The stomach is bulky and ex- 
tends for about half the length of the manu- 
brium when the latter is contracted. The lips 
are very broad and much folded ; each is pointed 
at the tip. Their margin is minutely crenate. 
The tentacles are very numerous, the normal 
number being at least 200. They are simple 
hollow structures, without basal bulbs or ad_ 
hesive pads. The distal part of each is long 
and filiform, but is very readily broken off. 
When this occurs the basal part persists as a 
finger-shaped process the tip of which is some- 
times a little introverted. On the distal part 
there are simple rings of nematocysts, which 
are directed outwards but by no means promi- 
nent. The tentacles have a definite arrange- 
ment, though it is liable to numerous minor 
irregularities. It is as follows: — near the base 
of each vertical canal, whether radial or centri- 
petal, a large tentacle arises in the jelly of the 
bell and arches downwards; between each pair 
of tentacles of this cycle three others, similar 
but slightly smaller, also arise in the jelly, and 
below these again, close to the margin, an indefinite number of much more slender 
tentacles are affixed to the surface. 
The sense-organs are minute and difficult to distinguish as they are completely 
concealed by the tentacles. They are arranged, sometimes in pairs, on the nerve-ring 
Fig. 5. — Asenathia ptscaioris, sp. nov. 
A minute portion of the margin of the 
bell showing one tentacle of each of the 
three circles, sense-organs, etc., x 50. 
The two larger tentacles are incomplete 
and only the upper part of the velum is 
shown. 
b = base of tentacle buried in the jelly. / = 
tentacle of upper circle, t = tentacle of middle 
circle, t = tentacle of lowest circle, s = sense 
organ, v = base of velum. 
